D.I.Y Pond Filter for Koi Pond

Hey guys, I have an outdoor pond filter with a built in UV. It’s all good and working and I have a waterfall connected to the water out end but I am debating about removing the water waterfall and building a big external filter at the back of the pond using gravel etc. I will then build a water fall outlet back into this or one of those cool spray bar things.

Anyhow. My first diy filter consisted of dirty water falling from a waterfall above and then filtering through layers of sponge and biomedia before coming out of the bottom. This was for a quarantine deck pond and it works exceptionally well.



I have seen other filters made where the dirty water comes through the bottom of the filter and then rises through layers of gravel etc before coming out the top.

Which is the better approach in your opinion? Also, is a tap necessary at the bottom to clean it out if I’m planning on putting plants inside.

I’ll obviously have my original internal filter still but the more the better

Thanks

Yes a cleaning valve is a very good idea

Very nice! I think for your next project, you are describing a bog filter. Yeah, up-flow is preferred. There are a bunch of videos on line showing how to do it. There is also an excellent UK site that specializes in ponds: https://www.gardenpondforum.com/
Click on 'what's new' and you will see a post today about bog filtration.
Let us know how it goes!

MaloK said:

Yes a cleaning valve is a very good idea

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This is great. Thank you. I was thinking to myself, what can I use at the bottom to elevate the tray where the sludge would collect at the bottom.

From your designs. I see two exit points for the pond? Is that two separate water falls? Or, do they meet up? Or, is it like a optional design depending on if I want one or outflows?

Archerfish said:

Very nice! I think for your next project, you are describing a bog filter. Yeah, up-flow is preferred. There are a bunch of videos on line showing how to do it. There is also an excellent UK site that specializes in ponds: https://www.gardenpondforum.com/
Click on 'what's new' and you will see a post today about bog filtration.
Let us know how it goes!

Click to expand...

Thank you for the link.

Mmm, I might have to re-consider the plants in the bog as one of the threads states that if the water is filtered before reaching the bog, there wouldn't be enough nutrients. I guess that depends a lot on how effective my filter is.

I'll keep you updated about how it goes.

Deeznuts said:

This is great. Thank you. I was thinking to myself, what can I use at the bottom to elevate the tray where the sludge would collect at the bottom.

From your designs. I see two exit points for the pond? Is that two separate water falls? Or, do they meet up? Or, is it like a optional design depending on if I want one or outflows?

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No, it's not optional. Both returns to the same waterfall.

MaloK said:

No, it's not optional. Both returns to the same waterfall.

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Been all over my town today trying to find trays or a plastic mesh panel that I can use at the bottom of the filter where the waste collects. Impossible!!

What’s the worse if I’m unable to create the bottom waste collecting part? Let’s say, if I put gravel straight on to the bottom?

If you do that, instead of having the incoming water pipe straight and pierced with holes.

Add a "T" with two small part of tube and two 90° elbows, that should help preventing too much buildup.

MaloK said:

If you do that, instead of having the incoming water pipe straight and pierced with holes.

Add a "T" with two small part of tube and two 90° elbows, that should help preventing too much buildup.

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I have used the lid that came with the box to makeshift the compartment at the bottom and connected the pipe.

I’ll have to go to my local pond shop tomorrow and see if they have the tank connectors for the water out and overflow as all the trade places close by only sell 22mm.

I wasn’t expecting a simple DIY filter to be so time-consuming lol

I have 27cm of room for gravel and bio balls etc.

Instead of using trays, I've found some nets with zips around the house. I'll house the bio balls and stuff in them.

I'll follow up tomorrow

MaloK said:

If you do that, instead of having the incoming water pipe straight and pierced with holes.

Add a "T" with two small part of tube and two 90° elbows, that should help preventing too much buildup.

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Yesterday was a nightmare trying to find attachments for piping, etc. On top of that, finding a fish-friendly PVC cement wasn’t easy either.

The progress is as follows:



For the bottom empty void tray.


I had to adjust the design and add a breather pipe below the two white over flow notches, too. If ever we have a power cut to prevent the water syphoning back into the pond.

The two over flow notches join to the water fall blade (dustpan).



You can see at the bottom, there was also a leak from the tap.

I used plumbers tape with no avail.

I’ll have to get some water sealant tomorrow and although it may look ugly, I’ll use a lot lol.

Also, top left and right, I have another two overflow connectors, connecting to two hoses.



The hoses may need extending a little.

I am almost there though haha.

I have the pebbles waiting to go in. After I know for certain there are no leaks, I’ll put the stones in.

I will also make the front look a little prettier, so the pipes aren’t visible and maybe connect the pipes to another two dustpans.

MaloK said:

If you do that, instead of having the incoming water pipe straight and pierced with holes.

Add a "T" with two small part of tube and two 90° elbows, that should help preventing too much buildup.

View attachment 347543

Click to expand...

Finally finished it.

Big rocks are very expensive here. I decided to choose pebbles of 50-80mm for the bottom layer.

20mm second layer and 10mm for the third layer.

I shall see how this works and play around with different media.

I was confused about whether you put plants in with soil or not.

There was mixed answers about that as some said they require soil to begin with. Some used baskets and others don’t etc. what’s your opinion on this?

I can always remove them from the soil if need be or just add some extra without soil.

See finished set up, minus the water fall. I need to amend and make this pretty lol. My out pipes are that even, so the water is coming out wonky lol